This invention relates to improved hydro-ski craft adapted to plane at high speeds along the surface of a body of water.
As a planing type boat moves along the surface of a body of water, the frictional drag on the boat tends to increase very rapidly as high speeds are attained; and also the susceptibility of the craft to overturning or damage by contact with even minor waves increases drastically. To reduce these adverse effects, there have been devised ski type marine craft which at high speed ride on skis or planing surfaces having a wetted area which is much smaller than the planing area which is in contact with the water at lower speeds. One such hydro-ski craft is shown in U.S. Pat. No. 3,308,780 issued Mar. 14, 1967, which discloses a boat having two skis adapted to be shifted vertically relative to the main hull of the boat between upper retracted positions for low speed travel and downwardly extended positions in which the skis alone support the craft at high speeds, with very effective load alleviation at high speeds as a result of the reduced area of contact of the skis with the water.
There has also been proposed in the past, in U.S. Pat. No. 2,647,709 issued Aug. 4, 1953, a type of landing ski for aircraft in which the effective area of the ski for contacting a body of water or the like can be varied. This landing ski has flaps at its opposite sides which are hinged to swing about longitudinal axes between positions in which the flaps supplement the water contacting area of a main central portion of the ski and retracted positions in which the central portion alone contacts the water or other supporting surface.